The present invention relates to a method for the preparation of a treatment machine for the treatment of a medical liquid comprising a coupling surface with actuators, with a cassette comprising a hard part with liquid conducting passages which are covered by a flexible film being able to be coupled to the coupling surface of the treatment machine so that the actuators can control the liquid flow in the liquid conducting passages by pressing the flexible film down into the cassette. The present invention furthermore comprises a corresponding treatment machine having a control for the carrying out of the method in accordance with the invention. The treatment machine in accordance with the invention is in particular a treatment machine for dialysis, in particular for peritoneal dialysis.
When setting up such a treatment machine, the required cassette, which is configured as a disposable article, has to be inserted into the machine and coupled to the coupling surface. For this purpose, the disposable cassette has a coupling plane for the coupling to the coupling surface of the treatment machine which is areally closed with a thin flexible polymer film so that different actuators and sensors of the treatment machine can couple to the outer film surface. The actuators can be valve tappets. The valve tappets press the flexible polymer film at different points into corresponding liquid conducting passages or recesses of the cassette and thus seal the liquid conducting passages.
For technical material and hygienic reasons it has previously not been possible to allow such a treatment machine, and indeed in particular a machine for automated peritoneal dialysis (APD), to be left in a waiting mode with an inserted cassette after the setting up. The spring-loaded valve tappets can cause a visco-elastic deformation (creep deformation) of the film, so-called sack formation, on a permanent pressure effect of the tappet onto the disposable film. Such a sack formation must, however, be avoided because otherwise the functional capability of the disposable cassette or of the valves formed by the actuators in interaction with the film can be impaired. Peritoneal dialysis patients who are treated by means of home peritoneal dialysis must therefore accept restrictions in their freedom of mobility in accordance with the methods known from the prior art because they are forced to start the treatment which lasts several hours immediately after the preparation (setting up) of the dialysis machine. This is generally accepted as inevitable by the patients and is not further questioned.
It is admittedly known that a first cycle of outflow and inflow can be carried out during the day and the automated peritoneal dialysis treatment can then be interrupted. The problem described above of material creep of the film also occurs in such a case. A regular movement of the valve tappets is automatically carried out in accordance with a specific logic during the interruption mode as a counter-measure against the creep deformation of the disposable film. It is prevented by this movement that the film deforms at the valve points due to a permanent pressure effect of the tappet. The additional cycle during the day admittedly improves the efficiency of the peritoneal dialysis, but further restricts the patient in his daily agenda.
With known treatment units, the treatment must in particular always be started immediately after the setting up of the treatment machine. The setting up of the dialyzer is, however, relatively time consuming and complex and comprises the steps of system check, inserting the cassette, inserting the solution bag connectors, connecting the drainage line, filling the cassette and the tubes. It would therefore be desirable for the improvement of the quality of life of the patient to design the procedures more flexibly and to reduce the restriction in the freedom of movement of the patient to the absolutely required amount so that the patient can participate in social life more flexibly.